Abstract

Endodontic-periodontal lesions are often observed in clinical situations. Although endodontic-periodontal lesions are encountered, they may pose difficulties for the clinician in diagnosis and may complicate the treatment. Diagnosis is often challenging because these diseases have been primarily studied as separate entities, and each primary disease may mimic the clinical characteristics of the other disease. In this report, a simple classification of endodontic-periodontal lesions is demonstrated, and presents a case of endodontic-periodontal disease in an immature tooth with a vertical bone defect showing retrograde periodontitis in which successful results were obtained by using infected root canal treatment and apexification with Vitapex? containing calcium hydroxide.

Keywords

Introduction

It is well-known that apical periodontitis is caused mainly
by bacteria and bacterial components from the root canal
system. Periapical bone destruction is the most characteristic
feature of acute purulent apical periodontitis [1,2]. In most
cases, the abscess destroys the relatively thin bone cortex
on the buccal or lingual side. Abscesses form under the
periosteum, causing the inflammation to expand further into
the surrounding soft tissue, which can result in the formation of fistula and a shift from acute apical periodontitis to chronic
apical periodontitis [3].

Endodontic-periodontal disease is a relatively familiar
disease; however, its etiology is not easily elucidated in daily
clinical practice [4–6]. Even carefully following the highest
standard of treatment will not always cure it, and refractory
apical periodontitis can then develop.

The characteristic features of each type of endodonticperiodontal
lesion are shown in Table 1. In this report, a
treatment course for Type 1a along with this classification,
endodontic-periodontal disease in an immature tooth with retrograde periodontitis, is demonstrated.

Pulp
condition

Periodontal pocket

Gutta-percha cone
into the sinus tract

X-ray finding

Type I
(Primary
endodontic lesions)

Non vital
pulp/
pulp less

A few deep pockets
(drainage path
through the
periodontal ligament
from the periapical
lesion )

The tip reach the
apical region

a: Clear radiolucent area
along the only one side
root
(U shape)
b: Furcation radiolucent
area

Significant periodontitis is
hardly seen

Type II
(Primary
periodontal lesions)

Vital
pulp

Extensive many
deep pockets

The tip does not
face the root
apex but heads
toward the
cervicular
portion.

Case Report

A 10-year-old girl visited with the chief complaint of
gingival swelling of the mandibular left premolar (Figure
2a). She was referred to the hospital for specialized care,
manifesting spontaneous pain (–), percussion pain (+), tooth
mobility (–), sinus tract (+), and apical pressure pain (±) in
35. Probing Periodontal Pocket Depth (PPD) of 35 was 6 mm,
with no bleeding on probing; PPD of the other teeth were
less than 2 mm (Figure 2b). Good oral hygiene was seen,
and neither deposits of plaque nor calculus were observed in the pocket. Radiographic examination revealed a prominent
radiolucent area extending to the root apex in the mesial site
of 35 (Figure 2c). A radiolucent area in the central portion of
the occlusal surface was observed (Figure 3a). A gutta-percha
cone through the sinus tract was used to close the root apex
(Figure 3b). Out of all the teeth, the vertical bone defect was
only observed at the mesial site of 35 (Figure 4).

Figure 2: Findings of tooth 35 at initial visit

Figure 3: X-ray findings of tooth 35 at initial visit

Figure 4: Ortho-pantomography finding at initial visit the vertical
bone defect (arrow) was only observed at the mesial site of 35

Infected root canal treatment and apexification were
implemented based on a clinical diagnosis of Type 1a endodonticperiodontal
disease (retrograde periodontitis) caused by a fracture
of the central cusp. After infected root canal treatment, reduction
of radiolucency and bone tissue regeneration were continuously
observed at the mesial site of 35 (Figures 5 and 6(a-d)).Root
canal filling was performed because a remarkable recovery of
bone tissue was observed from the apex to the marginal portion
and the open apex was closed nine months after the infected root
canal treatment (Figure 7a).

Figure 5: Findings of tooth 35 of infected root canal treatment at
initial visit a gutta-percha cone was located under the open apex.

Figure 6: Findings of tooth 35 during apexification

Figure 7: Findings of tooth 35 after root canal filling

Two years and four months after the root canal filling,
no radiolucent area was observed and the alveolar bone
height showed the same level as the neighboring teeth. The
prognosis has been favorable, with a clear laminar dura at the
mesial site of 35 (Figures 7b and 7c).

Discussion

The central nodule that is commonly found in the
mandibular second premolar is a conical or short rod like small
protrusion seen in the central part of the occlusal surface. As
a result, when this protrusion breaks during occlusion, the
pulp is exposed, which may cause apical periodontitis from
pulpitis, so clinical attention is required. It has been generally
reported that bacterial infection spreads to the pulp cavity
due to a coronal fracture caused by trauma, and suppurative
inflammation often happens in the dental pulp tissue. It has
also been suggested that pulpal necrosis occurs as a sequel
of pulpitis or traumatic injury, and then apical periodontitis
is caused by bacteria and bacterial products from the root
canal system [3]. Although rare, it has been demonstrated
that periapical inflammation can develop into retrograde
periodontitis [7]. In this case, a deep narrow pocket was seen
at just one aspect of the root surface and open to the gingival
sulcus or the bottom of the existing periodontal pocket.

In general, chronic periodontitis is a common plaqueinduced
periodontal infection that shows connective
attachment loss followed by activation of bone resorption.
Furthermore, in progressive periodontitis, wedge-shaped
vertical bone defects, many deep periodontal pockets and the
accumulation of large amounts of plaque are observed [8].

Because the patient in this case was 10 years old,
it was hard to believe that she could be suffering from
chronic periodontitis at this age. Additionally, hardly any
accumulation of plaque was observed in the gingival sulcus.
A horizontal bone defect image was observed at the mesial
side in the X-ray findings and a periodontal pocket of 6 mm
was only seen in the buccal mesial side of the diseased tooth
root. This periodontal pocket disappeared quickly after the
root canal treatment, and the X-ray findings revealed that
bone tissue had recovered to a healthy level after root canal filling. From these findings, it is inferred that the resorption
image of the alveolar bone at the marginal portion observed
in this case was a different lesion from the true marginal
periodontitis characterized by the attachment loss.

It is well-known that the first choice of treatment for
Type 1 endodontic-periodontal disease caused by apical
periodontitis is infected root canal treatment [4–6]. In
addition, intervention by periodontal treatment after followup
should be considered. Conversely, it has been suggested
that root formation and apical closure are possible in immature
teeth as long as the Herdwig’s epithelial sheath survives,
even when the pulp is infected and necrosed [9,10]. It is thus
important to be careful not to damage the periodontal tissue
of the apical portion by over instrumentation and over filling
beyond the apical foramen.

A prerequisite that forms the basis of infected root canal treatment appears to be not to damage the apical periodontal
tissue but to activate its self-repairing ability by eliminating
inflammatory factors in the root canal and to enhance the healing
mechanisms of the periapical region. It is therefore necessary
to keep the Vitapex® containing calcium hydroxide inside the
root canal. Elongation of the root and closure of the open apex
were observed as a result of root canal treatment in which the
work length was set so that the calcium hydroxide preparation
did not come into direct contact with the apical periodontal
tissue [11–14]. In this case, a slight elongation of the apical
apex was observed two years and four months after root canal
filling without intervention by periodontitis treatment. In recent
years, the possibility of hard tissue formation resulting from
differentiation of the Stem Cells of the Apical Papilla (SCAP)
has been suggested [15,16]. It is thought that elongation of the
apical root and healing of the alveolar bone were induced by
providing an effective environment for restoring the function of the Herdwig’s epithelial sheath and activating the SCAP.
Recently, Regenerative Endodontic Therapy (RET) has attracted
attention [17]. It was reported that RET and apexification
achieved a comparable outcome in regard to the resolution of
symptoms and apical healing in the treatment of immature teeth
with the periapical lesion [18].

It has been demonstrated that the pathway of endodontic
inflammation is through the apical foramen, furcation canals,
and lateral accessory canals to the periodontal ligament in the
endodontic-periodontal lesions [3]. In addition, endodonticperiodontal
diseases are caused by various factors such as
perforation and root fracture [9-22]. Therefore, the clinician
needs to bear in mind that the successful outcome is based
on accurate diagnosis during the treatment of the confusing
endodontic-periodontal problem.

Conclusion

The results confirm the importance of accurate
examination and diagnosis using clinical examination and
precise observation of the X-ray findings in the treatment of
endodontic-periodontal disease (primary endodontic lesion)
showing retrograde periodontitis and open apex.

Acknowledgement

The authors confirm that there are no conflicts of interest
related to this study.